The present disclosure relates to the field of molds for molding and vulcanizing a tire tread. More specifically, the disclosure relates to the molds used for molding in the tread grooves which are partially or completely covered by an additional cover layer.
WO2012087826 discloses a molding element of a mold for molding and vulcanizing a tire tread. The molding element comprises a molding surface intended to mold part of the tire tread surface and a rib intended to mold a groove in the tread. In addition, the molding element comprises two lamellas positioned on either side of the rib at a certain distance from this rib, each lamella comprising a cutting edge, this cutting edge making an acute angle. The cutting edge is able to cut a cover layer that covers a green tire, The rib itself will mold a groove in the tread and at the same time guide part of the cover layer into the groove thus molded.
Document WO03089257 discloses a pneumatic tire which has fine grooves formed in a tread surface for improve brake and drive performance on ice-bound roads in early periods of wear, and which prevents snow clogging in the fine grooves, thereby enabling a further enhancement of the effect of improving the brake and drive performance.
There is a need to improve the conception of the mold for molding fine groove on the tread surface of the tire and in the same time incorporating a covering layer.
A “tire” means all types of elastic tire whether or not subjected to an internal pressure.
A “green tire” or “green form” of a tire means a superposition of a plurality of semi-finished rubber products present in the form of strips or sheets, with or without reinforcement. The green tire is intended to be vulcanized in a mold in order to obtain the tire.
The “tread” of a tire means a quantity of rubber material bounded by lateral surfaces and by two main surfaces one of which is intended to come into contact with a road surface when the tire is running.
A “tread surface” means the surface formed by those points on the tire tread that come into contact with the road surface when the tire is running.
A “mold” means a collection of separate molding elements which, when brought closer towards one another, delimit a toroidal molding space.
A “molding element” of a mold means part of a mold. A molding element is, for example, a mold segment.
A “rib” of a molding element means a protrusion projecting from the molding surface. A rib is intended to mold a groove in the tire tread. The width of the groove is 2 mm or more.
A “lamella” of a molding element means a protrusion projecting from the molding surface. A lamella is intended to mold a ripe in the tire tread The width of the lamella is less than 2 mm.
A “rib with a rounded end” means that the end of the rib is domed,
An “acute angle” means an angle smaller than 90°.